thread

thread /n./ [Usenet, GEnie, CompuServe] Common abbreviation
of `topic thread', a more or less continuous chain of postings on
a single topic. To `follow a thread' is to read a series of
Usenet postings sharing a common subject or (more correctly) which
are connected by Reference headers. The better newsreaders can
present news in thread order automatically.

Interestingly, this is far from a neologism. The OED says:
"That which connects the successive points in anything, esp. a
narrative, train of thought, or the like; the sequence of events
or ideas continuing throughout the whole course of anything;"
Citations are given going back to 1642!